/Engine/Plugins/Runtime/MassEntity/Source/MassEntity/Public/MassExternalSubsystemTraits.h
Note that we're not supplying a default value for this property to be able to statically catch code that tries to access given subsystem without including the appropriate headers. See the comment above if you want to use aUWorldSubsystemthat has not had its traits defined before. GameThreadOnly = true,
enum { ThreadSafeRead = false }